建筑物对临河站日照时数观测的影响与订正

The Effects of Buildings on the Sunshine Duration Measurement at Linhe Station and Its Correction

摘要: 为计算楼房对临河站日照的影响，特引用棒影比率计算公式，算出冬至日8:00和16:00，楼房与日照计的临界距离，即楼房与日照计高度差的11.38倍。临河站日照计距地面6 m，高度为18 m和15 m的楼房与其高度差分别为12 m和9 m，它们与日照计的临界距离为136.6 m和102.4 m。而在1985~2009年24年间，西北-正西向15 m高的楼房与日照计的最近距离为86.7 m；在1994~2009年15年间，西-西南方向18 m高的楼房与日照计的最近距离为96.0 m，在2000~2009年9年间，东-东南方向18米两栋楼房最近距离分别为84.8 m和119.6 m。因此三个方位的楼房均影响光线进入日照计。1959~1984年临河站冬半年平均日照时数为1438.1 h，1985~2009年为1330.7 h，减少107.4 h，减幅为7.5%。陕坝站对应年代日照时数分别为1420.6 h和1423.7 h，增加3.1 h，增幅0.2%。临河迁站后，2010~2017年，冬半年平均日照时数为1442.9 h，比建楼前增加4.8 h，增幅0.3%。陕坝站对应年代日照时数1448.5 h，增加27.9 h，增幅为1.9%。利用相临陕坝站的资料，建立临河站日照时数订正方程，方程均通过0.01的显著性检验，历史拟合较好。

Abstract: To investigate the buildings’ effects on the sunshine duration measurement at Linhe station, we adopted stick-shadow formula, which is 11.38 times the height difference between a building and sunshine recorder, to calculate the required critical distance at 8:00 am and 4:00 pm on the day of winter solstice. At Linhe station, the solar recorder is sited at a height of 6 m; a height difference to 18 m high and 15 m high buildings is 12 m and 9 m respectively, so the calculated critical distance for these two buildings are 136.6 m and 102.4 m. Over the 24 years from 1985 to 2009, the closet distance between a 15 m high building situated in northwest-west and sunshine recorder is 86.7 m; Over the 15 years from 1994 to 2009, the closest distance of 18 m high building situated in west-southwest to the sunshine recorder is 96.0 m; from 2000 to 2009, closest distance between two buildings of 18 m in height located in east-southeast to recorder is 84.8 m and 119.6 m. Therefore, the buildings located in all three directions affect the measurement of sunshine duration collection. The mean total sunshine duration data collected by Linhe station over winter-half year from 1959 to 1984 was 1438.1 hours and dropped to 1330.7 hours from 1985 to 2009, which is decreased by 107.4 hours (7.5%). At Shanba station, for the same time periods, the sunshine duration increased from about 1420.6 hours to 1423.7 hours, increased by 3.1 hours (0.2%). After the relocation of Linhe station, the average sunshine duration over winter-half year from 2010 to 2017 was about 1442.9 hours, increased by 4.8 hours (0.3%) compared to the old station where buildings around were not constructed yet (1959-1984). At the same time, the average sunshine duration of Shanba station was about 1448.5 hours respectively, increased by 27.9 hours (1.9%). For providing more accurate meteorological information, an empirical model was developed by using data from Shanba station to correct the buildings’ effects on the measurement of sunshine duration at Linhe station. The developed empirical model has statistical significance of 0.01 and is in a good coincidence.